Instead of mixing 100 gr coffee beans (grounded) : 700ml water, and having a cold brew coffee concentrate later you can mix with water/ice. How about if I make, for example, 100gr coffee beans (grounded) to 1400ml water, and then later having ready to drink coffee (no need to mix with water) and just maybe mix it with milk...?

It won't be the same. Aside from the beverage aspect, this is an extraction. When you change the parameters, i.e. the ratio of coffee grounds to water, the result would be different, maybe better, maybe worse. You would do well to first adjust your grind and/or contact time, and see where that goes. A concentrate will be easier to store and use on demand than the finished product imo...

As the risk of being booed off the forum for self promotion (hopefully not bad form since I think I'm answering some of the questions), I wrote an article that talks about several techniques for cold brewing. The categories I cover includes Straight Cold Brew, Hot Brew then Cool, Coffee Frappé (similar to what Starbucks calls Frappuccino), and an instant Jamaica shaker. I can't say it includes step by step instructions. But, there are some helpful tips. It includes some pictures as well:

As the risk of being booed off the forum for self promotion (hopefully not bad form since I think I'm answering some of the questions), I wrote an article that talks about several techniques for cold brewing. The categories I cover includes Straight Cold Brew, Hot Brew then Cool, Coffee Frappé (similar to what Starbucks calls Frappuccino), and an instant Jamaica shaker. I can't say it includes step by step instructions. But, there are some helpful tips. It includes some pictures as well:

Since the new Tasting Wheel and Lexicon was released by the SCAA and ongoing coffee research, here are my thoughts, Tweeted earlier this week, on the depth and complexity of cold brew.
Please note that this is for professional use only.

Since the new Tasting Wheel and Lexicon was released by the SCAA and ongoing coffee research, here are my thoughts, Tweeted earlier this week, on the depth and complexity of cold brew.
Please note that this is for professional use only.

Thank you for the heads up regarding the AdSense block that isn't showing up. It's likely a caching plugin that is doing this (I have been wondering if the caching plugin did this and you have confirmed it for me). I'm sorry you feel like the page has too many ads. I try to follow guidelines for a "minimalist" number of ads (two ad blocks total on the page and in the "recommended" places). I see two ads on this forum, but I guess maybe they are positioned "better"? I guess I should re-think my strategy for ad placement (it's not working great anyway). I do appreciate the feedback.

Anyway, I hope the cold brew content was at least helpful for the question asked (if you got past the broken ads).

Thank you for the heads up regarding the AdSense block that isn't showing up. It's likely a caching plugin that is doing this (I have been wondering if the caching plugin did this and you have confirmed it for me). I'm sorry you feel like the page has too many ads. I try to follow guidelines for a "minimalist" number of ads (two ad blocks total on the page and in the "recommended" places). I see two ads on this forum, but I guess maybe they are positioned "better"? I guess I should re-think my strategy for ad placement (it's not working great anyway). I do appreciate the feedback.

Anyway, I hope the cold brew content was at least helpful for the question asked (if you got past the broken ads).

Regards,
sjmyst

I'm glad you figured out what was happening.

I didn't exactly say that you have too many ads on your webpage, I just mentioned that I hate looking at webpages that have tons of ads on them. A couple of ads are okay, but even on this Coffee Forums webpage, sometimes there are more than that, and it get's to be pretty annoying.

You did have some interesting content for cold brew recipes that I'm sure people will find helpful. The photos made me crave an iced mocha with lots of whipped cream, and I don't even drink iced coffee.

We do cold brew at our coffee shop. We use kegs and nitrogen to propel it out of the tap an into cups with ice. This has worked great, however, we started having a problem with the cold brew going sour in our kegs. We have cleaned the lines, professionally, cleaned the kegs, only use distilled water... I just can't figure out why its souring. Do you have any suggestions? I'm completely lost as to why. It stays refrigerated at all times. We do brew it toddy method in a commercial refrigerator and if we keep it in glass containers it seems to stay just fine. Do you think the kegs are reacting with the acidity?
Help!

Maybe you have this problem figured out by now. But I'll pipe in anyways. I too had my coffee go sour in the kegs after a day or so. Then I switched to 100% nitrogen instead of the 75/25 Nitro/co2 beer gas and I have not had an issue since. Conclusion is the Co2 was souring the coffee. Not sure if you are running 100% or not. I did have to add a carbonating stone to my kegs to get the nitrogen to absorb into the coffee. Now I get a nice cascading "Guinness" like pour.

A fridge would be better as far as the coffee not being diluted when the ice melts. I doubt that the flavor would be different if kept at room temps, and don't think the concentrate will go bad either, but would suggest keeping it cold to be sure.

For how long out of the fridge would you say it is safe? My gf had some bad experience in the summer as the coffee was out of the fridge for only one day, it grew mould ^^' She would not like to keep it on the fridge as it would get the 'fridge taste'.